CIVICRM-552 Inherited memberships are converted to individual memberships when the "parent" for the membership is merged with another contact

Inherited memberships are converted to individual memberships when the "parent" for the membership is merged with another contact.

Steps to reproduce:

1. Create an organisation based Membership Type
2. Set Membership Type inheritance based on "Employer of" relationship
3. Create Organisation A
4. Create Individual A
5. Create relationship "Employer of" from Organisation A to Individual A
6. Create Membership for Organisation A
7. Note, inherited Membership automatically created for Individual A
8. Create Organisation B
9. Merge Organisation A and Organisation B
10. Bug: Individual A now has individual Membership which was not inherited by Parent

Expected result: Membership should have been removed.

An additional variation is that if both Organisation A and Organisation B have a membership then after the Organisation merging, the Individual A has two individual Memberships.

Agileware Reference, CIVICRM-552